A DC power supply and load monitoring and protection device

Abstract

The present invention discloses a DC power supply and load monitoring protection device, including a power supply module, a load module, a control switch, an isolation module, a bias module, a judgment module, an output module and a control module. The control switch includes a switch input end, a switch output end and a switch control end. The output end of the power supply module is connected to the switch input end, the switch output end is connected to the input end of the isolation module, the input end of the bias module and the input end of the load module are both connected to the output end of the isolation module, the output end of the bias module is connected to the input end of the output module through the judgment module, and the output end of the output module is connected to the switch control end through the control module. In the present invention, the power supply module supplies power to the equipment of the load module through the isolation module, and the bias module adds a bias monitoring signal to the power supply line. The judgment module samples and monitors the power supply line and the load in real time, so as to quickly control the control switch to shut down the line through the control module.

Description

Technical Field

[0001] The present invention relates to the field of electronic circuits, and in particular to a direct current power supply and a load monitoring and protection device. Background Art

[0002] At present, there is a need for low-voltage DC short-distance power supply in many occasions in the field of electronic circuit applications, especially for occasions with high requirements for power supply stability and availability. It is necessary to monitor the online status of the power supply line and load-end equipment in real time and quickly protect and restore in case of abnormalities. In response to such needs, the traditional approach is to add management IC and return signal line (or wireless return) at the load device end. This method requires additional transmission wires or transmission equipment, which greatly increases the construction cost of the project, and cannot meet the requirements for the renovation of old lines that have already been laid. For a type of solution that uses AC high-frequency carriers to return information on the power line, there is an unavoidable interference problem. For the urgent needs of power supply, line monitoring, load monitoring, protection and recovery of this two-wire DC power supply line, how to meet the above needs with low interference and low cost has become a problem that needs to be solved in this field. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a DC power supply and load monitoring and protection device, which can solve the problems of high cost and high interference in the prior art for realizing DC power supply line and load equipment monitoring, protection and self-recovery.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A DC power supply and load monitoring and protection device, comprising a power supply module for an external power supply, a load module for providing electric energy to an electric device, a control switch for driving a line between the power supply module and the load module to be in one of the states of on and off, an isolation module for isolating the control switch and the load module, a bias module for generating a bias signal and a sampling signal, a judgment module for analyzing and judging the sampling signal and generating judgment information, an output module for outputting the judgment information, and a control module for driving the control switch to be in one of the states of on and off, wherein the control switch comprises a switch input terminal for inputting an electric signal, a switch output terminal for outputting an electric signal, and a switch control terminal for driving the input terminal and the output terminal to be in one of the states of on and off, the output terminal of the power supply module is connected to the switch input terminal, the switch output terminal is connected to the input terminal of the isolation module, the input terminal of the bias module and the input terminal of the load module are both connected to the output terminal of the isolation module, the output terminal of the bias module is connected to the input terminal of the output module through the judgment module, and the output terminal of the output module is connected to the switch control terminal through the control module.

[0006] Preferably, the power supply module includes an inductor L1, a capacitor EC24 and a resettable fuse F7. The power supply is connected to one end of the resettable fuse F7 through the inductor L1. The other end of the resettable fuse F7 and one end of the capacitor EC24 are both connected to the switch input end. The other end of the capacitor EC24 is grounded.

[0007] Preferably, the isolation module includes a three-terminal regulator VR4 and a diode D33, the input terminal Vin of the three-terminal regulator VR4 is connected to the switch output terminal, the output terminal Vout of the three-terminal regulator VR4 is connected to the positive electrode of the diode D33, the input terminal of the bias module and the input terminal of the load module are both connected to the negative electrode of the diode D33. The ground terminal GND of the three-terminal regulator VR4 is grounded.

[0008] Preferably, the load module includes a transient suppression diode D18, a common-mode inductor L8 and an output terminal P1, the first end of the common-mode inductor L8, the input end of the bias module and the output end of the isolation module are all connected to the cathode of the transient suppression diode D18, the third end and the fourth end of the common-mode inductor L8 are both connected to the output terminal P1, and the anode of the transient suppression diode D18 and the second end of the common-mode inductor L8 are both grounded.

[0009] Preferably, the bias module includes a bias power supply and a bias circuit, the bias power supply includes a resistor R1353, a zener diode DZ6 and a capacitor EC31, one end of the resistor R1353 is connected to the output end of the power supply module, the other end of the resistor R1353, the cathode of the zener diode DZ6 and one end of the capacitor EC31, the input end of the judgment module, the input end of the load module and the output end of the isolation module are all connected to the bias circuit, and the anode of the zener diode DZ6 and the other end of the capacitor EC31 are grounded.

[0010] Preferably, the bias module includes a resistor R1353, a voltage zener diode DZ6, a capacitor EC31, a resistor R136, a capacitor C68, a capacitor EC29, a resistor R150 and a diode D21, the other end of the resistor R1353, the cathode of the voltage zener diode DZ6 and one end of the capacitor EC31 are all connected to one end of the resistor R136, the input end of the load module and the output end of the isolation module are both connected to the cathode of the diode D21, the anode of the diode D21 is connected to one end of the resistor R150, the other end of the resistor R150, the other end of the resistor R136, one end of the capacitor EC29 and one end of the resistor R150 are all connected to the input end of the judgment module, and the anode of the voltage zener diode DZ6, the other end of the capacitor EC31 and the other end of the capacitor EC29 are all grounded.

[0011] Preferably, the judgment module includes an operational amplifier U23A, an operational amplifier U23B, a capacitor C88, a resistor R137, a resistor R151, a resistor R155, a capacitor EC30 and a capacitor C69, the other end of the resistor R1353, the cathode of the voltage zener diode DZ6, one end of the capacitor EC31, one end of the capacitor C88 and one end of the resistor R136 are all connected to one end of the resistor R137, the reverse input end of the operational amplifier U23B and one end of the resistor R155 are all connected to the other end of the resistor R137, the other end of the resistor R150, the other end of the resistor R136, one end of the capacitor EC29 and the resistor One end of R150 and the reverse input end of the operational amplifier U23A are connected to the positive input end of the operational amplifier U23B, the other end of the resistor R155 and the positive input end of the operational amplifier U23A are connected to one end of the resistor R155, the output end of the operational amplifier U23A and the output end of the operational amplifier U23B are connected to the output module, one end of the capacitor EC30, one end of the capacitor C69, and the power supply input end of the operational amplifier U23A are connected to the output end of the power supply module, and the other end of the capacitor C88, the other end of the capacitor EC30, the other end of the capacitor C69, and the ground end of the operational amplifier U23 are all grounded.

[0012] Preferably, the output module includes a first output circuit and a second output circuit, the first output circuit includes a light-emitting diode D25, a resistor R153 and a photocoupler U27, the output end of the operational amplifier U23A is connected to the cathode of the light-emitting diode D25, the anode of the light-emitting diode D25 is connected to the cathode of the transmitting end of the photocoupler U27 through the resistor R153, the anode of the transmitting end of the photocoupler U27 is connected to the output end of the power supply module, the cathode of the receiving end of the photocoupler U27 is grounded, and the output end of the operational amplifier U23B is connected to the control module through the second output circuit.

[0013] Preferably, the second output circuit includes a light-emitting diode D23, a resistor R142 and a photocoupler U22, the output end of the operational amplifier U23B is connected to the cathode of the light-emitting diode D23, the anode of the light-emitting diode D23 is connected to the cathode of the transmitting end of the photocoupler U22 through the resistor R142, the cathode of the transmitting end of the photocoupler U22 is connected to the output end of the power supply module, and the cathode of the receiving end of the photocoupler U22 is grounded.

[0014] Preferably, the control module includes a photocoupler U32 and a photocoupler U33, the negative pole of the transmitting end of the photocoupler U32 is connected to the negative pole of the transmitting end of the photocoupler U22, the positive pole of the transmitting end of the photocoupler U33 and the positive pole of the transmitting end of the photocoupler U32 are both connected to the output end of the power supply module, the negative pole of the transmitting end of the photocoupler U33 is connected to the negative pole of the transmitting end of the photocoupler U27, the positive pole of the receiving end of the photocoupler U32 is connected to the switch control end, the negative pole of the receiving end of the photocoupler U32 is connected to the positive pole of the receiving end of the photocoupler U33, and the negative pole of the receiving end of the photocoupler U33 is grounded.

[0015] Compared with the prior art, the beneficial effect of the present invention is that: the equipment of the load module is powered by the power supply module through the control switch and the isolation module, and the bias module adds a bias monitoring signal to the power supply line (between the isolation module and the load module). Specifically, by adding a DC bias signal to the low-voltage DC power supply line, and then sampling the DC signal from the power supply line, judging and controlling whether the control switch of the DC power supply line is continuously opened, the state monitoring of the low-voltage two-wire DC power supply line, the line load end monitoring and the line protection / recovery control are realized, wherein the monitoring signal is a DC signal, which will not affect the original DC power supply quality, and has the characteristic of non-interference. In combination with the sampling module and the judgment module, the power supply line and the load are sampled and monitored in real time. Once the line is monitored to be open, short-circuited or the load is abnormal, the control module is quickly used to control the control switch to shut down the line. When the line or load returns to normal, the control switch connects the line, thereby realizing the protection of the power supply equipment of the power supply module and the line, and at the same time, the line status information is output through the output module to realize communication with third-party equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the DC power supply and load monitoring and protection device described in the present invention.

[0017] Figure 2 The circuit diagram of the DC power supply and load monitoring and protection device described in the present invention.

[0018] Figure 3 It is a circuit diagram of the power supply module described in the present invention.

[0019] Figure 4 It is a circuit diagram of the control switch described in the present invention.

[0020] Figure 5 4 is a circuit diagram of the isolation module described in the present invention.

[0021] Figure 6 is a circuit diagram of the load module described in the present invention.

[0022] Figure 7 is a circuit diagram of the bias module described in the present invention.

[0023] Figure 8 It is a circuit diagram of the judgment module described in the present invention.

[0024] Fig. 9 is a circuit diagram of the output module described in the present invention.

[0025] Fig.10 is a circuit diagram of the control module described in the present invention. DETAILED DESCRIPTION

[0026] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0027] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] Below, the present invention is further described in conjunction with the accompanying drawings and specific embodiments:

[0030] like Figure 1-10As shown, in the present invention, a DC power supply and load monitoring and protection device includes a power supply module for an external power supply, a load module for providing electrical energy to electrical equipment, a control switch for driving a line between the power supply module and the load module to be in one of an on and off state, an isolation module for isolating the control switch and the load module, a bias module for generating a bias signal and a sampling signal, a judgment module for analyzing and judging the sampling signal and generating judgment information, an output module for outputting judgment information and a control module for driving the control switch to be in one of an on and off state. Preferably, the power supply is a DC power supply. Specifically, the power supply module supplies power to the equipment of the load module through the control switch and the isolation module, and adds a bias monitoring signal to the power supply line (between the isolation module and the load module) through the bias module. The judgment module samples and monitors the power supply line and the load in real time. Once the line is monitored to be open, short-circuited or the load is abnormal, the control module is used to quickly control the control switch to shut down the line. When the line or load returns to normal, the control switch connects the line to protect the power supply equipment of the power supply module and the line. At the same time, the line status information is output through the output module to realize communication with third-party equipment.

[0031] Specifically, the control switch includes a switch input end for inputting an electrical signal, a switch output end for outputting an electrical signal, and a switch control end for driving the input end and the output end to be in one of an on and off state. The output end of the power supply module is connected to the switch input end, the switch output end is connected to the input end of the isolation module, the input end of the bias module and the input end of the load module are both connected to the output end of the isolation module, the output end of the bias module is connected to the input end of the output module through the judgment module, and the output end of the output module is connected to the switch control end through the control module. Preferably, the control switch includes a field effect tube Q12, a capacitor C65 and a resistor R134, and the field effect tube Q12, the capacitor C65 and the resistor R134 constitute a control switch of the power supply line. Specifically, the source of the field effect tube Q12, one end of the capacitor C65 and one end of the resistor R134 are all connected to the output end of the power supply module, the other end of the capacitor C65, the other end of the resistor R134 and the output end of the control module are all connected to the gate of the field effect tube Q12, and the drain of the field effect tube Q12 is connected to the input end of the isolation module; in this embodiment, the resistor R134 provides a pull-up for the gate of the field effect tube Q12 to make the field effect tube Q12 closed by default, and the capacitor C65 provides a short delay for the opening of the field effect tube Q12, and the on-off of the DC line (the DC line refers to the line from the output end of the power supply module to the input end of the load module) is controlled by controlling the on-off between the source and the drain of the field effect tube Q12, so that when a fault occurs, hot plugging can be performed without arc discharge, and plug and play is achieved.

[0032] Preferably, the power supply module includes an inductor L1, a capacitor EC24 and a resettable fuse F7, the power supply is connected to one end of the resettable fuse F7 through the inductor L1, the other end of the resettable fuse F7 and one end of the capacitor EC24 are both connected to the switch input end, and the other end of the capacitor EC24 is grounded. In this embodiment, the power supply module is used to input a DC voltage in the range of 3-100V to the DC line, the inductor L1 and the capacitor EC24 form an LC filter to preliminarily purify the input power supply, and the resettable fuse F7 performs current limiting protection on the entire DC line.

[0033] Preferably, the isolation module includes a three-terminal voltage regulator VR4 and a diode D33, the input terminal Vin of the three-terminal voltage regulator VR4 is connected to the switch output terminal, the output terminal Vout of the three-terminal voltage regulator VR4 is connected to the positive electrode of the diode D33, and the input terminal of the bias module and the input terminal of the load module are both connected to the negative electrode of the diode D33. The ground terminal GND of the three-terminal voltage regulator VR4 is grounded. Preferably, the three-terminal voltage regulator VR4 adopts a 78 series three-terminal voltage regulator, and the voltage from the power supply module is linearly stepped down to obtain a new voltage U1 lower than the power supply module voltage (VIN24_1), which is transmitted to the power line through the diode D33, and the diode D33 is used to isolate the reverse flow of other signal voltages on the power line.

[0034] Preferably, the load module includes a transient suppression diode D18, a common mode inductor L8 and an output terminal P1, the first end of the common mode inductor L8, the input end of the bias module and the output end of the isolation module are all connected to the cathode of the transient suppression diode D18, the third end and the fourth end of the common mode inductor L8 are both connected to the output terminal P1, and the anode of the transient suppression diode D18 and the second end of the common mode inductor L8 are both grounded. In this embodiment, the transient suppression diode D18 is used for transient suppression of interference such as line surge, and the common mode inductor L8 is used for suppressing line common mode interference, and is used to protect the circuit from being affected by interference signals from the DC line.

[0035] Preferably, the bias module includes a resistor R1353, a voltage zener diode DZ6, a capacitor EC31, a resistor R136, a capacitor C68, a capacitor EC29, a resistor R150 and a diode D21, the other end of the resistor R1353, the cathode of the voltage zener diode DZ6 and one end of the capacitor EC31 are all connected to one end of the resistor R136, the input end of the load module and the output end of the isolation module are both connected to the cathode of the diode D21, the anode of the diode D21 is connected to one end of the resistor R150, the other end of the resistor R150, the other end of the resistor R136, one end of the capacitor EC29 and one end of the resistor R150 are all connected to the input end of the judgment module, and the anode of the voltage zener diode DZ6, the other end of the capacitor EC31 and the other end of the capacitor EC29 are all grounded. Preferably, the resistor R1353, the voltage stabilizing diode DZ6 and the capacitor EC31 form a bias power supply, and the resistor R136, the capacitor C68, the capacitor EC29, the resistor R150 and the diode D21 form a bias circuit. In the present embodiment, the bias power supply stabilizes the voltage (VIN24_1) from the output end of the power supply module to U2 (U2 is about 3V larger than U1), the resistor R136, the resistor R150 and the diode D21 add U2 to the DC line, the resistor R136 and the resistor R150 are used for current limiting, the capacitor EC29 and the capacitor C68 are used for voltage filtering, and the diode D21 limits the reverse flow of the bias voltage. Since the bias module adds an independent bias power supply, it is ensured that there is still a bias monitoring signal on the line after the power supply line is turned off, which can realize the real-time automatic monitoring and automatic recovery functions after the abnormal shutdown of the line. Preferably, resistor R136, capacitor C68, capacitor EC29, resistor R150 and diode D21 also constitute a sampling module, that is, the sampling module shares the bias circuit part of the bias module, and the sampling principle is: after the bias power supply voltage U2 is biased to the power supply line, if the line is open (the load device does not exist or is short-circuited), the bias voltage on the line cannot form a current loop, and the sampling voltage U3 is equal to U2; if the line is short-circuited, the bias voltage on the line forms a maximum current to the ground through resistor R136, resistor R150, and diode D21. Due to the voltage division of resistors R136 and R150, U3 is the smallest at this time, which is about 1 / 4U2 voltage; if the load device is connected to the line and the device works normally, the bias voltage on the line will drop slightly (the bias power supply voltage has a small supply current and a voltage about 3V higher, and the new voltage U1 has a large supply current and a voltage about 3V lower), which is about 9 / 10U2. The state of the line and the state of the load can be determined by the voltage range sampled back.

[0036] Preferably, the judgment module includes an operational amplifier U23A, an operational amplifier U23B, a capacitor C88, a resistor R137, a resistor R151, a resistor R155, a capacitor EC30 and a capacitor C69, the other end of the resistor R1353, the cathode of the voltage zener diode DZ6, one end of the capacitor EC31, one end of the capacitor C88 and one end of the resistor R136 are all connected to one end of the resistor R137, the reverse input end of the operational amplifier U23B and one end of the resistor R155 are all connected to the other end of the resistor R137, the other end of the resistor R150, the other end of the resistor R136, one end of the capacitor EC29 and the resistor One end of R150 and the reverse input end of the operational amplifier U23A are connected to the positive input end of the operational amplifier U23B, the other end of the resistor R155 and the positive input end of the operational amplifier U23A are connected to one end of the resistor R155, the output end of the operational amplifier U23A and the output end of the operational amplifier U23B are connected to the output module, one end of the capacitor EC30, one end of the capacitor C69, and the power supply input end of the operational amplifier U23A are connected to the output end of the power supply module, and the other end of the capacitor C88, the other end of the capacitor EC30, the other end of the capacitor C69, and the ground end of the operational amplifier U23 are all grounded. In this embodiment, resistor R137, resistor R151 and resistor R155 provide reference voltages for operational amplifier U23A and operational amplifier U23B by means of voltage division. The reference voltage points are 1 / 4U2 and 9 / 10U2 respectively, that is, 1 / 4U2 is input to the positive input terminal of operational amplifier U23A and 9 / 10U2 is input to the reverse input terminal of operational amplifier U23B. Capacitor EC30 and capacitor C69 are bypass capacitors, which play a role in purifying the power supply of the operational amplifier. The sampling voltage U3 is respectively sent to the reverse input terminal of operational amplifier U23A and the positive input terminal of operational amplifier U23B, and is operated with the reference voltages 1 / 4U2 and 9 / 10U2. When U3≤1 / 4U2, the power supply line is short-circuited and the operation is performed. Pin 7 of the operational amplifier outputs a low voltage (approximately 0V), and pin 1 outputs a high voltage (approximately VIN24_1); when 1 / 4U2<U3≤9 / 10U2, the line load is normal, pin 7 of the operational amplifier outputs a low voltage (approximately 0V), and pin 1 outputs a low voltage (approximately 0V); when U3>9 / 10U2, the power line is open, pin 7 of the operational amplifier outputs a high voltage (approximately VIN24_1), and pin 1 outputs a low voltage (approximately 0V). The judgment module can correspond the three states of the line to three groups of signal voltages, and realize signal output and automatic control (due to the real-time existence of the line bias signal, the real-time judgment of the line and load conditions can be realized, including the line and load after the abnormal situation is shut down).

[0037] Preferably, the output module includes a first output circuit and a second output circuit, the first output circuit includes a light-emitting diode D25, a resistor R153 and a photocoupler U27, the output end of the operational amplifier U23A is connected to the cathode of the light-emitting diode D25, the anode of the light-emitting diode D25 is connected to the cathode of the transmitting end of the photocoupler U27 through the resistor R153, the anode of the transmitting end of the photocoupler U27 is connected to the output end of the power supply module, the cathode of the receiving end of the photocoupler U27 is grounded, and the output end of the operational amplifier U23B is connected to the control module through the second output circuit. Specifically, the second output circuit includes a light-emitting diode D23, a resistor R142 and a photocoupler U22, the output end of the operational amplifier U23B is connected to the cathode of the light-emitting diode D23, the anode of the light-emitting diode D23 is connected to the cathode of the transmitting end of the photocoupler U22 through the resistor R142, the anode of the transmitting end of the photocoupler U22 is connected to the output end of the power supply module, and the cathode of the receiving end of the photocoupler U22 is grounded. In this embodiment, resistors R142 and R153 are used for current limiting, light-emitting diodes D23 and D25 are used for status indication, and photoelectric couplers U22 and U27 are used for signal voltage conversion, which are used to convert high-voltage signals into low-voltage signals and send them to external microcontrollers and other devices, so that external devices can obtain the judgment information issued by the judgment module.

[0038] Preferably, the control module includes a photocoupler U32 and a photocoupler U33, the negative pole of the transmitting end of the photocoupler U32 is connected to the negative pole of the transmitting end of the photocoupler U22, the positive pole of the transmitting end of the photocoupler U33 and the positive pole of the transmitting end of the photocoupler U32 are both connected to the output end of the power supply module, the negative pole of the transmitting end of the photocoupler U33 is connected to the negative pole of the transmitting end of the photocoupler U27, the positive pole of the receiving end of the photocoupler U32 is connected to the switch control end, the negative pole of the receiving end of the photocoupler U32 is connected to the positive pole of the receiving end of the photocoupler U33, and the negative pole of the receiving end of the photocoupler U33 is grounded. In this embodiment, the gate of the field effect transistor Q12 of the control switch is pulled down by two series connection. Only when the output end of the operational amplifier U23B of the judgment module and the output end of the operational amplifier U23A both output low voltage (the line load is normal), the two series-connected photoelectric couplers will be turned on, and the field effect transistor Q12 can be turned on to achieve continuous power supply to the power line. In other cases, one photoelectric coupler is always not turned on, which causes the field effect transistor Q12 to be turned off, and the power supply line of the abnormal power line is cut off to protect the power supply module and the line wiring. After the DC line is powered on again, the bias power supply signal is always present. The two share two power lines, and the appropriate voltage difference is adjusted to ensure that they do not interfere with each other, so as to achieve self-recovery after protection.

[0039] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A monitoring and protection device for a DC power supply and a load, characterized in that: The invention comprises a power supply module for an external power supply, a load module for providing electric energy to an electric device, a control switch for driving a line between the power supply module and the load module to be in one of the states of on and off, an isolation module for isolating the control switch and the load module, a bias module for generating a bias signal and a sampling signal, a judgment module for analyzing and judging the sampling signal and generating judgment information, an output module for outputting judgment information, and a control module for driving the control switch to be in one of the states of on and off. The control switch comprises a switch input terminal for inputting an electric signal, a switch output terminal for outputting an electric signal, and a switch control terminal for driving the input terminal and the output terminal to be in one of the states of on and off. The output terminal of the power supply module is connected to the switch input terminal, the switch output terminal is connected to the input terminal of the isolation module, the input terminal of the bias module and the input terminal of the load module are both connected to the output terminal of the isolation module, the output terminal of the bias module is connected to the input terminal of the output module through the judgment module, and the output terminal of the output module is connected to the switch control terminal through the control module. The load module includes a transient suppression diode D18, a common-mode inductor L8 and an output terminal P1. The first end of the common-mode inductor L8, the input end of the bias module and the output end of the isolation module are all connected to the cathode of the transient suppression diode D18, the third end and the fourth end of the common-mode inductor L8 are both connected to the output terminal P1, and the anode of the transient suppression diode D18 and the second end of the common-mode inductor L8 are both grounded.

2. The monitoring and protection device for a DC power supply and a load as claimed in claim 1, characterized in that: The power supply module includes an inductor L1, a capacitor EC24 and a resettable fuse F7. The power supply is connected to one end of the resettable fuse F7 through the inductor L1. The other end of the resettable fuse F7 and one end of the capacitor EC24 are both connected to the switch input end. The other end of the capacitor EC24 is grounded.

3. The monitoring and protection device for a DC power supply and a load as claimed in claim 1, characterized in that: The isolation module includes a three-terminal regulator VR4 and a diode D33, wherein the input terminal Vin of the three-terminal regulator VR4 is connected to the switch output terminal, the output terminal Vout of the three-terminal regulator VR4 is connected to the positive electrode of the diode D33, the input terminal of the bias module and the input terminal of the load module are both connected to the negative electrode of the diode D33, and the ground terminal GND of the three-terminal regulator VR4 is grounded.

4. The monitoring and protection device for a DC power supply and a load as claimed in claim 1, characterized in that: The bias module includes a bias power supply and a bias circuit. The bias power supply includes a resistor R1353, a voltage zener diode DZ6 and a capacitor EC31. One end of the resistor R1353 is connected to the output end of the power supply module, and the other end of the resistor R1353, the cathode of the voltage zener diode DZ6 and one end of the capacitor EC31, the input end of the judgment module, the input end of the load module and the output end of the isolation module are all connected to the bias circuit. The anode of the voltage zener diode DZ6 and the other end of the capacitor EC31 are grounded.

5. The monitoring and protection device for a DC power supply and a load as claimed in claim 4, characterized in that: The bias module includes a resistor R1353, a voltage-stabilizing diode DZ6, a capacitor EC31, a resistor R136, a capacitor C68, a capacitor EC29, a resistor R150 and a diode D21. The other end of the resistor R1353, the cathode of the voltage-stabilizing diode DZ6 and one end of the capacitor EC31 are all connected to one end of the resistor R136. The input end of the load module and the output end of the isolation module are both connected to the cathode of the diode D21. The anode of the diode D21 is connected to one end of the resistor R150. The other end of the resistor R150, the other end of the resistor R136, one end of the capacitor EC29 and one end of the capacitor C68 are all connected to the input end of the judgment module. The other end of the capacitor C68 is grounded. The anode of the voltage-stabilizing diode DZ6, the other end of the capacitor EC31 and the other end of the capacitor EC29 are all grounded.

6. The monitoring and protection device for a DC power supply and a load as claimed in claim 5, characterized in that: The judgment module includes an operational amplifier U23A, an operational amplifier U23B, a capacitor C88, a resistor R137, a resistor R151, a resistor R155, a capacitor EC30 and a capacitor C69. The other end of the resistor R1353, the cathode of the voltage zener diode DZ6, one end of the capacitor EC31, one end of the capacitor C88 and one end of the resistor R136 are all connected to one end of the resistor R137. The reverse input end of the operational amplifier U23B and one end of the resistor R151 are all connected to the other end of the resistor R137. The other end of the resistor R150, the other end of the resistor R136, one end of the capacitor EC29 and one end of the capacitor C68 are connected to the operational amplifier U23B. The reverse input terminal of the operational amplifier U23A is connected to the positive input terminal of the operational amplifier U23B, the other end of the resistor R151 and the positive input terminal of the operational amplifier U23A are connected to one end of the resistor R155, the other end of the resistor R155 is grounded, the output terminal of the operational amplifier U23A and the output terminal of the operational amplifier U23B are connected to the output module, one end of the capacitor EC30, one end of the capacitor C69, and the power supply input terminal of the operational amplifier U23A are connected to the output terminal of the power supply module, and the other end of the capacitor C88, the other end of the capacitor EC30, the other end of the capacitor C69, and the ground terminal of the operational amplifier U23A are all grounded.

7. The monitoring and protection device for a DC power supply and a load as claimed in claim 6, characterized in that: The output module includes a first output circuit and a second output circuit. The first output circuit includes a light-emitting diode D25, a resistor R153 and a photocoupler U27. The output end of the operational amplifier U23A is connected to the cathode of the light-emitting diode D25. The anode of the light-emitting diode D25 is connected to the cathode of the transmitting end of the photocoupler U27 through the resistor R153. The anode of the transmitting end of the photocoupler U27 is connected to the output end of the power supply module. The cathode of the receiving end of the photocoupler U27 is grounded. The output end of the operational amplifier U23B is connected to the control module through the second output circuit.

8. The monitoring and protection device for a DC power supply and a load as claimed in claim 7, characterized in that: The second output circuit includes a light-emitting diode D23, a resistor R142 and a photocoupler U22. The output end of the operational amplifier U23B is connected to the cathode of the light-emitting diode D23. The anode of the light-emitting diode D23 is connected to the cathode of the transmitting end of the photocoupler U22 through the resistor R142. The anode of the transmitting end of the photocoupler U22 is connected to the output end of the power supply module. The cathode of the receiving end of the photocoupler U22 is grounded.

9. The monitoring and protection device for a DC power supply and a load as claimed in claim 8, characterized in that: The control module includes a photoelectric coupler U32 and a photoelectric coupler U33, wherein the negative pole of the transmitting end of the photoelectric coupler U32 is connected to the negative pole of the transmitting end of the photoelectric coupler U22, the positive pole of the transmitting end of the photoelectric coupler U33 and the positive pole of the transmitting end of the photoelectric coupler U32 are both connected to the output end of the power supply module, the negative pole of the transmitting end of the photoelectric coupler U33 is connected to the negative pole of the transmitting end of the photoelectric coupler U27, the positive pole of the receiving end of the photoelectric coupler U32 is connected to the switch control end, the negative pole of the receiving end of the photoelectric coupler U32 is connected to the positive pole of the receiving end of the photoelectric coupler U33, and the negative pole of the receiving end of the photoelectric coupler U33 is grounded.

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